【轉】成型濾波與匹配濾波的MATLAB實現

轉載自：https://blog.csdn.net/yuan1164345228/article/details/45919315

 

Fd=1;  
Fs=8;   
Delay=3;   
R=0.5;   
[yf,tf]=rcosine(Fd,Fs,'fir/sqrt',R,Delay);  
figure(1);
plot(yf); grid;title('根升余弦濾波器時域波形')
x=randint(100,1)*2-1;%原始輸入信號為+1，-1碼    
xt=zeros(1,800);    
xt(1:8:end)=x; %%插值后信號
y1=filter(yf,tf,xt); %%成型濾波  
y2=filter(yf,tf,y1); %%用與發送端相同的根升余弦匹配濾波
yt=y2((size(yf)+1)/2:8:end);%%匹配濾波后抽取        
figure(2);    
stem(x(1:40)); grid;title('原始信號輸出');
figure(3);
plot(y1(1:100));grid;title('成型信號輸出');
figure(4);
plot(y2(1:100));grid;title('匹配濾波信號輸出');
figure(5);    
stem(yt(1:40)); grid;title('抽取后信號輸出') ;

　　

濾波器的截止頻率是Fd/2；Fs/Fd是內插倍數；其頻響可以由滾降系數和窗長(FIR階數)確定。 
delay * (Fs / Fd) * 2 + 1就是濾波器的階數